1. Field of the Invention
This invention relates generally to improved regeneration of liquid desiccants of the type found in air conditioners which utilize liquid desiccants for dehumidifying air.
2. Description of the Related Art
The use of hydroscopic liquids, such as lithium chloride (LiCl), lithium bromide (LiBr) or calcium chloride (CaCl.sub.2) solutions, to dehumidify air are well known. However, use of these devices has been limited owing to problems associated with regenerating (i.e., removing water from) the liquid desiccant. Regeneration generally requires contacting the liquid desiccant with hot gas which absorbs the excess moisture or heating the liquid desiccant to drive off excess moisture. The heated air regenerators are costly to operate especially where waste heat is not available. Utilization of boiler-type regenerators is found to be expensive, requiring specialty corrosion-resistant metals. If pressurized boilers are employed to provide higher efficiency operation, costly components are needed and safety issues become more complex.
U.S. Pat. No. 4,939,906, entitled Multi-Stage Boiler/Regenerator For Liquid Desiccant Dehumidifiers, issued on July 10, 1990, and invented by Mark W. Spatz and John J. Tandler, describe a liquid desiccant rejuvenation system which uses both a desiccant boiler and an evaporator/condenser. The evaporator/condenser unit, coupled in series with the desiccant boiler serves as a preconditioning unit for the desiccant boiler unit. Some energy reuse is disclosed, however, all of the desiccant to be regenerated must be introduced into the desiccant boiler unit.
A need has therefore been felt for apparatus and an associated method which can provide regeneration of hydroscopic liquids while reducing the liquid heat exchange needs for the process and reducing the requirements for specialized materials in fabricating the apparatus.